Reforming of hydrocarbons with a platinum-tungsten-germanium catalyst

ABSTRACT

HYDROCARBONS ARE CONVERTED BY CONTACTING AT CONVERSION CONDITIONS, WITH A CATALYTIC COMPOSITE COMPRISING COMBINATION OF CATALYTICALLY EFFECTIVE AMOUNTS OF A PLATINUM GROUP COMPONENT, A GROUP VI-B TRANSITION METAL COMPONENT AND A GROUP IV-A METALLIC COMPONENT WITH A POROUS CARRIER MATERIAL. A SPECIFIC EXAMPLE OF THE DISCLOSED HYDROCARBON CONVERSION PROCESS IS A PROCESS FOR THE REFORMING OF A GASOLINE FRACTION IN WHICH THE GASOLINE FRACTION AND HYDROGEN ARE CONTACTED, AT REFORMING CONDITIONS, WITH A CATALYTIC COMPOSITE COMPRISING A COMBINATION OF CATALYTICALLY EFFECTIVE AMOUNTS OF A PLATINUM COMPONENT, PONENT, A TUNGSTEN COMPONENT, A GERMANIUM COMPONENT, AND A HALOGEN COMPONENT WITH AN ALUMINA CARRIER MATERIAL.

United States Patent US. Cl. 208-139 Claims ABSTRACT OF THE DISCLOSUREHydrocarbons are converted by contacting, at conversion conditions, witha catalytic composite comprising a combination of catalyticallyeffective amounts of a platinum group component, a Group VI-B transitionmetal component and a Group IV-A metallic component with a porouscarrier material. A specific example of the disclosed hydrocarbonconversion process is a process for the reforming of a gasoline fractionin which the gasoline fraction and hydrogen are contacted, at reformingconditions, with a catalytic composite comprising a combination ofcatalytically effective amounts of a platinum component, a tungstencomponent, a germanium component, and a halogen component with analumina carrier material.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is a divisionof my prior, copending application Ser. No. 17,886 which was filed onMar. 9, 1970, now abandoned.

DISCLOSURE The subject of the present invention is a novel catalyticcomposite which has exceptional activity and resistance to deactivationwhen employed in a hydrocarbon conversion process that requires acatalyst having both a hydrogenation-dehydrogenation function and acracking function. More precisely, the present invention involves anovel dual-function catalytic composite which, quite surprisingly,enables substantial improvements in hydrocarbon conversion processesthat have traditionally used a dual-function catalyst. In anotheraspect, the present invention comprehends the improved processes thatare produced by the use of a catalytic composite comprising acombination of a platinum group component, a Group VI-B transition metalcomponent, and a Group IV-A metallic component with a porous carriermaterial; specifically, an improved reforming process which utilizes thesubject catalyst to to improve activity, selectivity, and stabilitycharacteristics.

Composites having a hydrogenation-dehydrogenation function and acracking function are widely used today as catalysts in many industries,such as the petroleum and petrochemical industry to accelerate a widespectrum of hydrocarbon conversion reactions. Generally, the crackingfunction is thought to be associated with an acid-acting material of theporous, adsorptive, refractory oxide type which is typically utilized asthe support or carrier for a heavy metal component such as the metals orcompounds of metals of Groups V through VIII of the Periodic Table towhich are generally attributed the hydrogenation-dehydrogenationfunction.

3,806,446 Patented Apr. 23, 1974 These catalytic composites are used toaccelerate a wide variety of hydrocarbon conversion reactions such ashydrocracking, isomerization, dehydrogenation, hydrogenation,desulfurization, cyclization, alkylation, polymerization, cracking,hydroisomerization, etc. In many cases, the commercial applications ofthese catalysts are in processes where more than one of these reactionsare proceeding simultaneously. An example of this type of process isreforming wherein a hydrocarbon feed stream containing paraffins andnaphthenes is subjected to conditions which promote dehydrogenation ofnaphthenes to aromatics, dehydrocyclization of paraffins to aromatics,isomerization of parafiins and naphthenes, hydrocracking of naphthenesand paraffins and the like reactions, to produce an octane-rich oraromatic-rich product stream. Another example is a hydrocracking processwherein catalysis of this type are utilized to effect selectivehydrogenation and cracking of high molecular weight unsaturatedmaterials, selective hydrocracking of high molecular weight materials,and other like reactions, to produce a generally lower boiling, morevaluable output stream. Yet another examplc is an isomerization processwherein a hydrocarbon fraction which is relatively rich instraight-chain paraffin components is contacted with a dual-functioncatalyst to produce an output stream rich in isoparaffin compounds.

Regardless of the reaction involved or the particular process involved,it is of critical importance that the dualfunction catalyst exhibit notonly the capability to initially perform its specified functions, butalso that it has the capability to perform them satisfactorily forprolonged periods of time. The analytical terms used in the art tomeasure how well a particular catalyst performs its intended functionsin a particular hydrocarbon reaction environment are activity,selectivity, and stability. And for purposes of discussion here, theseterms are conveniently defined for a given charge stock as follows: (1)activity is a measure of the catalysts ability to convert hydrocarbonreactants into products at a sepcified severity level where severitylevel means the conditions used-that is, the temperature, pressure,contact time, and presence of diluents such as H (2) selectivity refersto the amount of desired product or products obtained relative to theamount of reactants converted; (3) stability refers to the rate ofchange with time of the activity and selectivity parameters-obviously,the smaller rate implying the more stable catalyst. In a reformingprocess, for example, activity commonly refers to the amount ofconversion that takes place for a given charge stock at a specifiedseverity level and is typically measured by octane number of the Cproduct stream; selectivity refers to the amount of C yield that isobtained at the particular severity level; and stability is typicallyequated to the rate of change with time of activity, as measured byoctane number of C product, and of selectivity, as measured by 0 yield.Actually, the last statement isnot strictly correct because generally acontinuous reforming process is run to produce a constant octane Cproduct with severity level being continuously adjusted to attain thisresult; and, furthermore, the severity level is for this process usuallyvaried by adjusting the conversion temperature in the reaction zone sothat, in point of fact, the rate of change of activity finds response inthe rate of change of conversion temperatures and changes in this lastparameter are customarily taken as indicative of activity stability.

As is well known to those skilled in the art, the principal cause ofobserved deactivation or instability of a dualfunction catalyst when itis used in a hydrocarbon conversion reaction is associated with the factthat coke forms on the surface of the catalyst during the course of thereaction. More specifically, in these hydrocarbon conversion processes,the conditions utilized typically result in the formation of heavy, highmolecular weight, black, solid or semi-solid, carbonaceous materialwhich coats the surface of the catalyst and reduces its activity byshielding its active sites from the reactants. In other words, theperformance of this dual-function catalyst is sensitive to the presenceof carbonaceous deposits on the surface of the catalyst. Accordingly,the major problem facing workers in this area of the art is thedevelopment of more active and selective catalytic composites that arenot as sensitive to the presence of these carbonaceous materials and/orhave the capability to suppress the rate of the formation of thesecarbonaceous materials on the catalyst. Viewed in terms of performanceparameters, the problem is to develop a dual-function catalyst havingsuperior activity, selectivity, and stability. In particular, for areforming process the problem is typically expressed in terms ofshifting and stabilizing the yield-octane relationshipC yield beingrepresentative of selectivity and octane being proportional to activity.

I have now found a dual-function catalytic composite which possessesimproved activity, selectivity, and stability when it is employed in aprocess for the conversion of hydrocarbons of the type which haveheretofore utilized dual-function catalytic composites such as processesfor isomerization, hydroisomerization, dehydrogenation, desulfurization,denitrogenization, hydrogenation, alkylation, dealkylation,hydrodealkylation, transalkylation, cyclization, dehydrocyclization,cracking, hydrocracking, reforming, and the like processes. Inparticular, I have found that a combination of catalytically effectiveamounts of a platinum group component, a Group VI-B transition metalcomponent, and a Group IV-A metallic component with a porous refractorycarrier material enables the performance of hydrocarbon conversionprocesses utilizing dual-function catalysts to be substantiallyimproved. Moreover, I have determined that a catalytic compositecomprising a combination of catalytically effective amounts of aplatinum component, a germanium component, a tungsten component, and ahalogen component with an alumina carrier material can be utilized tosubstantially improve the performance of a reforming process whichoperates on a gasoline fraction to produce a high-octane reformate. Inthe case of a reforming process, the principal advantage associated withthe use of the novel catalyst of the present invention involves theacquisition of the capability to operate in a stable manner in a highseverity operation; for example, a low pressure reforming processdesigned to produce a C reformate having an octane of about 100 F-lclear. As indicated, the present invention essentially involves thefinding that the addition of a Group IV-B transition metal component anda Group IV-A metallic component to a duol-function hydrocarbonconversion catalyst containing a platinum group component enables theperformance characteristics of the catalyst to be sharply and materiallyimproved.

It is, accordingly, one object of the present invention to provide ahydrocarbon conversion catalyst having superior performancecharacteristics when utilized in a hydrocarbon conversion process. Asecond object is to provide a catalyst having dual-function hydrocarbonconversion performance characteristics that are relatively insensitiveto the deposition of hydrocarbonaceous material thereon. A third objectis to provide preferred methods of preparation of this catalyticcomposite which insures the achievement and maintenance of itsproperties. Another object is to provide an improved reforming catalysthaving superior activity, selectivity, and stability. Yet another objectis to provide a dual-function hydrocarbon conversion catalyst whichutilizes a combination of a Group VI-B transition metal component and aGroup IV-A metallic component to promote a platinum metal component.

In brief summary, the present invention is, in one embodiment, acatalytic composite comprising a combination of catalytically elfectiveamounts of a platinum group component, a Group VI-B transition metal,and a Group IV-A metallic component with a porous carrier material. Theporous carrier material is typically a porous, refractory material suchas a refractory inorganic oxide, and the Goup VI-B component, the GroupIV-A component, and the platinum group component are usually utilized inrelatively small amounts which are effective to promote the desiredhydrocarbon conversion reaction.

A second embodiment relates to a catalytic composite comprising acombination of catalytically effective amounts of a platinum component,a tungsten component, a germanium component, and a halogen componentwith an alumina carrier material. These components are preferablypresent in the composite in amounts sufficient to result in the finalcomposite containing, on an elemental basis, about 0.1 to about 3.5 wt.percent halogen, about 0.01 to about 2 wt. percent platinum, about 0.01to about 3 wt. percent tungsten, and about 0.01 to about 5 wt. percentgermanium.

Another embodiment relates to a catalytic composite comprising acombination of the catalytic composite disclosed in the first embodimentwith a sulfur component in an amount sufficient to incorporate about0.05 to about 0.5 wt. percent sulfur, calculated on an elemental basis.

Another embodiment relates to a process for the conversion of ahydrocarbon comprising contacting the hydrocarbon and hydrogen with thecatalytic composite described above in the first embodiment athydrocarbon conversion conditions.

A preferred embodiment relates to a process for reforming a gasolinefraction which comprises contacting the gasoline fraction and hydrogenwith the catalytic composite described above in the second embodiment atreforming conditions selected to produce a high-octane reformate.

Other objects and embodiments of the present invention relate toadditional details regarding preferred catalytic ingredients, preferredamounts of these ingredients, suitable methods of composite preparation,operating conditions for use in the hydrocarbon conversion processes,and the like particulars. These are hereinafter given in the followingdetailed dicussion of each of these facets of the present invention.

As indicated above, the catalyst of the present invention comprises aporous carrier material or support having combined therewithcatalytically effective amounts of a platinum group component, a GroupVI-B transition metal component, a Group IV-A metallic component, and inthe preferred case, a halogen component. Considering first the porouscarrier material, it is preferred that the material be a porous,adsorptive, high-suface area support having a surface area of about 25to about 500 m. gm. The porous carrier material should be relativelyrefractory to the conditions utilized in the hydrocarbon conversionprocess, and it is intended to include within the scope of the presentinvention carrier materials which have traditionally been utilized indual-function hydrocarbon conversion catalysts such as: (l) activatedcarbon, coke, or charcoal; (2) silica or silica gel, silicon carbide,clays, and silicates including those synthetically prepared andnaturally occurring, which may or may not be acid treated, for example,attapulgus clay, china clay, diatomaceous earth, fullers earth, kaolin,kieselguhr, etc.; (3) ceramics, porcelain, crushed firebrick, bauxite;(4) refractory inorganic oxides such as alumina, titanium dioxide,zirconium dioxide, chromium oxide, zinc oxide,

magnesia, thoria, boria, silica-alumina, silica-magnesia,chromia-alumina, alumina-boria, silica-zirconia, etc.; (5) crystallinealuminosilicates such as naturally occurring or synthetically preparedmordenite and/or faujasite, either in the hydrogen form or in a formwhich has been treated with multivalent cations; and (6) combination ofone or more elements from these groups. The preferred porous carriermaterials for use in the present invention are refractory inorganicoxides, with best results obtained with an alumina carrier material.Suitable alumina materials are the crystalline aluminas known as thegamma-, eta-, and theta-aluminas with gamma-alumina giving best results.In addition, in some embodiments, the alumina carrier material maycontain minor proportions of other well-known refractory inorganicoxides such as silica, zirconia, magnesia, etc.; however, the preferredsupport is substantially pure gamma-alumina. Preferred carrier materialshave an apparent bulk density of about 0.3 to about 0.7 gm./ cc. andsurface area characteristics such that the average pore diameter isabout 20 to 300 angstroms, the pore volume is about 0.1 to about 1 ml./gm. and the surface area is about 100 to about 500 m. /gm. In general,excellent results are typically obtained with a gamma-alumina carriermaterial which is used in the form of spherical particles having: arelatively small diameter (i.e., typically about inch), an apparent bulkdensity of about 0.5 gm./cc., a pore volume of about 0.4 ml./gm., and asurface area of about 175 mF/gm.

The preferred alumina carrier material may be prepared in any suitablemanner and may be synthetically prepared or natural occurring. Whatevertype of alumina is employed it may be activated prior to use by one ormore treatments including drying, calcination, steaming, etc., and itmay be in a form known as activated alumina, activated alumina ofcommerce, porous alumina, alumina gel, etc. For example, the aluminacarrier may be prepared by adding a suitable alkaline reagent, such asammonium hydroxide to a salt of aluminum such as aluminum chloride,aluminum nitrate, etc., in an amount to form an aluminum hydroxide gelwhich upon drying and calcining is converted to alumina. The aluminacarrier may be formed in any desired shape such as spheres, pills,cakes, extrudates, powders, granules, etc., and utilized in any desiredsize. For the purpose of the present invention a particularly preferredform of alumina is the sphere; and alumina spheres may be continuouslymanufactured by the well-known oil drop method which comprises; formingan alumina hydrosol by any of the techniques taught in the art andpreferably by reacting aluminum metal with hydrochloric acid; combiningthe resulting hydrosol with a suitable gelling agent; and dropping theresultant mixture into an oil bath maintained at elevated temperatures.The droplets of the mixture remain in the oil bath until they set andform hydrogel spheres. The spheres are then continuously withdrawn fromthe oil bath and typically subjected to specific aging treatments in oiland an ammoniacal solution to further improve their physicalcharacteristics. The resulting aged and gelled particles are then washedand dried at a relatively low temperature of about 300 F. to about 400F. and subjected to a calcination procedure at a temperature of about850 F. to about 1300 F. for a period of about 1 to about 20 hours. Thistreatment eflects conversion of the alumina hydrogel to thecorresponding crystalline gamma-alumina. See the teachings of U.S. Pat.No. 2,620,- 314, for additional details.

One essential constituent of the instant catalytic composite is thegroup IV-A metallic component. By the use of the generic term Group IV-Ametallic componen it is intended to cover the metals and compounds ofthe metals of Group IV-A of the Periodic Table. More specifically, it isintended to cover: germanium and the compounds of germanium; tin and thecompounds of tin; lead and the compounds of lead; and mixtures of thesemetals and/or compounds of metals. This group IV-A 6 metallic componentmay be present in the catalytic composite as an elemental metal, or inchemical combination with one or more of the other ingredients of thecomposite, or as a chemical compound of the Group IV-A metal such as theoxide, sulfide, halide, oxyhalide, oxychloride, aluminate, and the likecompounds. Based on the evidence currently available, it is believedthat best results are obtained when the Group IV-A metallic componentexists in the final composite in an oxidation state above that of theelemental metal, and the subsequently described oxidation and reductionsteps, that are preferably used in the preparation of the instantcomposite, are believed to result in a catalytic composite whichcontains an oxide of the Group lV-A metallic component such as germaniumoxide, tin oxide and lead oxide. Regardless of the state in which thiscomponent exists in the composite, it can be utilized therein in anyamount which is catalytically effective, with the preferred amount beingabout 0.01 to about 5 wt. percent thereof, calculated on an elementalbasis. The exact amount selected within this broad range is preferablydetermined as a function of the particular Group IV-A metal that isutilized. For instance, in the case where this component is lead, it ispreferred to select the amount of this component from the low end ofthis range-namely, about 0.01 to about 1 Wt. percent. Additionally, itis preferred to select the amount of lead as a function of the amount ofthe platinum group component as explained hereinafter. In the case wherethis component is tin, it is preferred to select from a relativelybroader range of about 0.05 to about 2 wt. percent thereof. And, in thepreferred case, where this component is germanium, the selection can bemade from the full breadth of the stated range-specifically,

about 0.01 to about 5 wt. percent, with best results at about 0.05 toabout 2 wt. percent. This Group IV-A component may be incorporated inthe composite in any suitable manner known to the art such as bycoprecipitation or cogelation with the porous carrier material, ionexchange with the carrier material, or impregnation of the carriermaterial at any stage in its preparation. It is to be noted that it isintended to include within the scope of the present invention allconventional procedures for incorporating a metallic component in acatalytic composite, and the particular method of incorporation used isnot deemed to be an essential feature of the present invention. However,best results are believed to be obtained when the Group IV-A componentis uniformly distributed throughout the porous carrier material. Oneacceptable method of incorporating the Group IV-A component into thecatalytic composite involves cogelling the Group IV-A component duringthe preparation of the preferred carrier material, alumina. This methodtypically involves the addition of a suitable soluble compound of theGroup IV-A metal of interest to the alumina hydrosol. The resultingmixture is then commingled with a suitable gelling agent, such as arelatively weak alkaline reagent and the resulting mixture is thereafterpreferably gelled by dropping into a hot oil bath as explainedhereinb-efore. After aging, drying and calcining the resulting particlesthere is obtained an intimate combination of the oxide of the Group IV-Ametal and alumina. One preferred method of incorporating this componentinto the composite involves utilization of a soluble, decomposablecompound of the particular Group IV-A metal of interest to impregnatethe porous carrier material either before, during or after the carriermaterial is calcined. In general, the solvent used during thisimpregnation step is selected on the basis of its capability to dissolvethe desired group lV-A compound without affecting the porous carriermaterial which is to be impregnated; ordinarily, good results areobtained when water is the solvent; thus the preferred Group IV-Acompounds for use in this impregnation step are typically water-solubleand decomposable. Examples of suitable Group IV-A compounds are:germanium difluoride, germanium tetrafluoride, germanium dioxide,germanium monosulfide, tin dibromide, tin dibromide di-iodide, tindichloride di-iodide, tin chromate, tin difiuoride, tin tetrafluoride,tin tetraiodide, tin sulfate, tin tartrate, lead acetate, lead bromate,lead bromide, lead chlorate, lead chloride, lead citrate, lead formate,lead lactate, lead malate, lead nitrate, lead nitrite, lead dithionate,and the like compounds. In the case where the Group IV-A component isgermanium, a preferred impregnation solution is germanium tetrachloridedissolved in anhydrous ethanol. In the case of tin, tin chloridedissolved in water is preferred. And in the case of lead, lead nitratein water is preferred. Regardless of which impregnation solution isutilized the Group lV-A component can be impregnated either prior to,simultaneously with, or after the other metallic components are added tothe carrier material. Ordinarily. best results are obtained when thiscomponent is impregnated simultaneously with the other metalliccomponents of the composite. Likewise, best results or ordinarilyobtained when the Group IV-A component is germanium or a compound ofgermanium.

Regardless of which Group IV-A compound is used in the preferredimpregnation step, it is important that the Group IV-A metalliccomponent be uniformly distributed throughout the carrier material. Inorder to achieve this objective it is necessary to maintain the pH ofthe impregnation solution in a range of about 1 to about 7 and to dilutethe impregnation solution to a volume which is substantially in excessof the volume of the carrier material which is impregnated, It ispreferred to use a volume ratio of impregnation solution to carriermaterial of at least 1.5 :1 and preferably about 2:1 to about 10:1 ormore. Similarly, it is preferred to use a relatively long contact timeduring the impregnation step ranging from about A hour up to about /2hour or more before drying to remove excess solvent in order to insure ahigh dispersion of the Group IV-A component on the carrier material. Thecarrier material is, likewise, preferably constantly agitated duringthis preferred impregnation step.

As indicated above, a second essential component of the subject catalystis the platinum group component. Although the process of the presentinvention is specifically directed to the use of a catalytic compositecontaining platinum, it is intended to include other platinum groupmetals such as palladium, rhodium, ruthenium, osmium, and iridium. Theplatinum group component such as platinum, may exist within the finalcatalytic composite as a compound such as an oxide, sulfide, halide,etc., or in chemical combinations with one or more of the other elementsof the composite, or as an elemental metal. Best results are thought tobe obtained when it is inthe elemental state. Generally, the amount ofthe platinum group component present in the final catalyst composite issmall compared to the quantities of the other components combinedtherewith. In fact, the platinum group component generally comprisesabout 0.01 to about 2 wt. percent of the final catalytic composite,calculated on an elemental basis. Excellent results are obtained Whenthe catalyst contains about 0.05 to about 1 wt. percent of the platinumgroup metal. The preferred platinum group component is platinum or acompound of platinum, although palladium and compounds of palladium givegood results.

The platinum group component may be incorporated in the catalyticcomposite in any suitable manner such as coprecipitation or cogelation,ion-exchange, or impregnation. The preferred method of preparing thecatalyst involves the utilization of a soluble, decomposable compound ofa platinum group metal to impregnate the carrier material. Thus, theplatinum group component may be added to the support by commingling thelatter with an aqueous solution of chloroplatinic acid. Otherwatersoluble compounds of platinum group metal may be em ployed inimpregnation solutions and include ammonium chloroplatinate,bromoplatinic acid, platinum dichloride, platinum tetrachloride hydrate,platinum dichlorocarbonyl dichloride, dinitrodiaminoplatinum, palladiumchloride, paladium sulfate, palladium nitrate, etc. The utilization of aplatinum chloride compound, such as chloroplatinic acid, is preferredsince it facilitates the incorporation of both the platinum componentand at least a minor quantity of the preferred halogen component in asingle step. Hydrogen chloride or the like acid is also generally addedto the impregnation solution in order to further facilitate theincorporation of the halogen component. In addition, it is generallypreferred to impregnate the carrier material after it has been calcinedin order to minimize the risk of washing away the valuable platinummetal compounds; however, in some cases it may be advantageous toimpregnate the carrier material when it is in a gelled state. Thiscomponent may be added after, before, or simultaneously with the othermetallic components, with the preferred procedure being simultaneousaddition.

Another essential ingredient of the instant catalyst is a Group VI-Btransition metal component. Included within the scope of this expressionare the metals and compounds of chromium, molybdenum, and tungsten, withtungsten and compounds of tungsten being especially preferred. Thiscomponent may exist within the final catalytic composite as a compoundsuch as the oxide, sulfide, halide or in chemical combination with oneor more of the other ingredients of the composite, or as an elementalmetal. Regardless of the exact chemical or physical nature of the forcesbinding this component to the final composite, it is preferred that thefinal composite contain about 0.01 to about 3 Wt. percent of thiscomponent, calculated on an elemental basis with the most preferredrange being about 0.05 to about 1 wt. percent. A particularly preferredcatalyst, for example, would contain, on an elemental basis, about 0.05to about 1 wt. percent tungsten. The function performed by thiscomponent is not entirely understood; however, I believe its primeinfluence is that it acts in conjunction with the Group IV-B metalliccomponent to promote and stabilize the platinum group component.

This Group VI-B transition metal component may be incorporated in thefinal composite in any suitable manner and at any stage in thepreparation thereof. One method involves impregnation of the porouscarrier material with a suitable solution of the Group VI-B transitionmetal at any stage in the preparation of the carrier material-that is,either as a hydrogel or after its calcination. Another method is theion-exchange method in which a solution of a suitable compound of theGroup VI-B transition metal, wherein the metal is present as anexchangeable ion, is contacted with the carrier material. Still anothermethod involves cogelation or coprecipitation of the Group VI-Bcomponent with the carrier material. The preferred method involvesimpregnation of the calcined carrier material with a solution containingthe Group VI-B transition metal; for example, excellent results areobtained by impregnating with aqueous solution of suitable Group VI-Bsalts such as ammonium tungstate, sodium tungstate, molybdenumtetrabromide, molybdic acid, chromium dibromide, chromium dichloride,chromium nitrate, sodium chlorate, amonium molybdate, etc., followed byconventional drying and calcination stens. Like the previous components,this component may be added before, during or after the addition of theother metallic components, with best results obtained with simultaneousaddition. For example, in the case of the preferredplatinumgermanium-tungsten catalyst, excellent results are obtained withan impregnation solution comprising a mixture of a first solutioncontaining chloroplatinic acid, hydrochloric acid, and ammoniumtungstate with a second solution containing germanium tetrachloridedissolved in anhydrous ethanol.

A preferred ingredient of the instant catalytic composite is a halogencomponent. Accordingly, a preferred embodiment of the present inventioninvolves a catalytic composite comprising a combination of catalyticallyeffective amounts of a platinum group component, a Group IV-A metalliccomponent, a Group VI-B transition metal component and a halogencomponent with an alumina carrier material. Although the precise form ofthe chemistry of the association of the halogen component with thecarrier material is not entirely known, it is customary in the art torefer to the halogen component as being combined with the carriermaterial, or with the other ingredients of the catalyst. This combinedhalogen may be either fluorine, chlorine, iodine, bromine, or mixturesthereof. Of these, fluorine and particularly chlorine are preferred forthe purposes of the present invention. The halogen may be added to thecarrier material in any suitable manner either during preparation of thecarrier material or before or after the addition of the othercomponents. For example, the halogen may be added at any stage of thepreparation of the carrier material or to the calcined carrier material,as an aqueous solution of an acid such as hydrogen fluoride, hydrogenchloride, hydrogen bromide, etc. The halogen component or a portionthereof may be composited with the carrier material during theimpregnation of the later vw'th the platinum group component; forexample, through the utilization of a mixture of chloroplatinic acid andhydrogen chloride. In another situation, the alumina hydrosol which istypically utilized to form the preferred alumina carrier material maycontain halogen and thus contribute at least a portion of the halogencomponent to the final composite. For reforming, the halogen will betypically combined with the carrier material in an amount sufiicient toresult in a final composite that contains about 0.1 to about 3.5 wt.percent, and preferably about 0.5 to about 1.5 Wt. percent of halogencalculated on an elemental basis. In isomerization or hydrocrackingembodiments, it is generally preferred to utilize relatively largeramounts of halogen in the catalyst--typically ranging up to about 10 Wt.percent halogen calculated on an elemental basis, and more preferablyabout 1 to about 5 wt. percent.

Regarding the preferred amounts of the various metallic components ofthe subject catalyst, I have found it to be a good practice to specifythe amounts of the Group VI-B transition metal component and of theGroup IV-A metallic component as a. function of the amount of theplatinum group component. On this basis, the amount of the Group VI-Btransition metal component is ordinarily selected so that the atomicratio of Group VI-B metal to the platinum group metal contained in thecomposite is about 0.05:1 to about 4:1, with the most preferred rangebeing about 0.1:1 to about 1:1. Similarly, the amount of the Group IV-Ametallic component is ordinarily selected to produce a compositecontaining an atomic ratio of Group IV-A metal to platinum group metalbetween the broad range of about 0.05 :1 to :1.

However, for the Group IV-A metal to platinum group metal ratio, thebest practice is to select this ratio on the basis of the followingpreferred range for the individual species: 1) for germanium, it isabout 0.3:1 to 10:1, with the most preferred range being about 0.6:1 to6:1; (2) for tin, it is about 0.121 to 3:1, with the most preferredrange being about 0.5 :1 to 1.5 :1; and (3) for lead, it is about 0.05:1to 09:1, with the most preferred range being about 0.1:1 to 0.75:1.

Another significant parameter for the subject catalyst is the totalmetals content which is defined to be the sum of the platinum groupcomponent, the Group VI-B transition metal component, and the Group IV-Ametallic component, calculated on an elemental metal basis. Good resultsare ordinarily obtained with the subject catalyst when this parameter isfixed at a value of about 0.15 to about 4 wt. percent, with best resultsordinarily 10 achieved at a metals loading of about 0.3 to about 2 wt.percent.

Integrating the above discussion of each of the essential and preferredingredients of the catalytic composite it is evident that a particularlypreferred catalytic composite for reforming comprises a combination of aplatinum component, a tungsten component, a germanium component, and ahalogen component with an alumina carrier material in amounts sufficientto result in the composite containing about 0.5 to about 1.5 wt. percenthalogen, about 0.05 to about 1 Wt. percent platinum, about 0.05 to about1 wt. percent tungsten and about 0.05 to about 2 wt. percent germanium.

In embodiments of the present invention wherein the instant catalyticcomposite is used for dehydrogenation of dehydrogenatable hydrocarbonsor for hydrogenation of hydrogenatable hydrocarbons, it is ordinarily apreferred practice to include an alkali or alkaline earth metalcomponent in the composite. More precisely, this optional component isselected from the group consisting of compounds of the alkalimetals-cesium, rubidium, potassium, sodium and lithium-and the compoundsof the alkaline earth metalcalcium, strontium, barium and magnesium.Generally, good results are obtained in these embodiments when thiscomponent constitutes about 0.1 to about 5 wt. percent of the composite,calculated on an elemental basis.

Regardless of the details of how the components of the catalyst arecombined with the porous carrier material, the final catalyst generallywill be dried at a temperature of about 200 to about 600 F. for a periodof from about 2 to about 24 hours or more, and finally calcined at atemperature of about 700 F. to about 1100 F. in an air atmosphere for aperiod of about 0.5 to about 10 hours in order to convert the metalliccomponents substantially to the oxide form. In the case where a halogencomponent is utilized in the catalyst, best results are generallyobtained when the halogen content of the catalyst is adjusted during thecalcination step by including water and a halogen or ahalogen-containing compound in the air atmosphere utilized. Inparticular, when the halogen component of the catalyst is chlorine, itis preferred to use a mole ratio of H 0 to HCl of about 20:1 to about100:1 during at least a portion of the calcination step in order toadjust the final chlorine content of the catalyst to a range of about0.5 to about 1.5 wt. percent.

Although it is not essential, it is preferred that the resultantcalcined catalytic composite be subjected to a substantially water-freereduction step prior to its use in the conversion of hydrocarbons. Thisstep is designed to insure a uniform and finely divided dispersion ofthe metallic components throughout the carrier material. Preferablysubstantially pure and dry hydrogen (i.e., less than 20 vol. p.p.m. H O)is used as the reducing agent in this step. The reducing agent iscontacted with the calcined catalyst at a temperature of about 800 F. toabout 1200 F. and for a period of time of about 0.5 to 10 hours or moreeffective to substantially reduce at least the platinum group componentto its elemental state. This reduction treatment may be performed insitu as part of a start-up sequence if precautions are taken to predrythe plant to a substantially water-free state and if substantiallywaterfree hydrogen is used.

The resulting reduced catalytic composite may, in many cases, bebeneficially subjected to a presulfiding operation designed toincorporate in the catalytic composite from about 0.05 to about 0.50 wt.percent sulfur calculated on an elemental basis. Preferably, thispresulfiding treatment takes place in the presence of hydrogen and asuitable sulfur-containing compound such as hydrogen sulfide, lowermolecular weight mercaptans, organic sulfides, etc. Typically, thisprocedure comprises treating the reduced catalyst with a sulfiding gassuch as a mixture of hydrogen and hydrogen sulfide having a mole rtaioof H to 1 1 H 8 of about :1 at conditions suflicient to effect thedesired incorporation of sulfur, generally including a temperatureranging from about 50 F. up to about 1100 F. or more. It is generally agood practice to perform this optional presulfiding step undersubstantially water-free conditions.

According to the present invention, a hydrocarbon charge stock andhydrogen are contacted with a catalyst of the type described above in ahydrocarbon conversion zone. This contacting may be accomplished byusing the catalyst in a fixed bed system, a moving bed system, afluidized bed system, or in a batch type operation; however, in view ofthe danger of attrition losses of the valuable catalyst and ofwell-known operational advantages, it is preferred to use a fixed bedsystem. In this system, a hydrogen-rich gas and the charge stock arepreheated by any suitable heating means to the desired reactiontemperature and then are passed, into a conversion zone containing afixed bed of the catalyst type previously characterized. It is, ofcourse, understood that the conversion zone may be one or more separatereactors with suitable means therebetween to insure that the desiredconversion temperature is maintained at the entrance to each reactor. Itis also important to note that the reactants may be contacted with thecatalyst bed in either upward, downward, or radial flow fashion with thelatter being preferred. In addition, the reactants may be in the liquidphase, a mixed liquid-vapor phase, or a vapor phase when they contactthe catalyst, with best results obtained in the vapor phase.

In the case where the catalyst of the present invention is used in areforming operation, the reforming system will comprise a reforming zonecontaining a fixed bed of the catalyst type previously characterized.This reforming zone may be one or more separate reactors with suitableheating means therebetween to compensate for the endothermic nature ofthe reactions that take place in each catalyst bed. The hydrocarbon feedstream that is charged to this reforming system will comprisehydrocarbon fractions containing naphthenes and parafiins that boilwithin the gasoline range. The preferred charge stocks are thoseconsisting essentially of naphthenes and parafiins, although in manycases aromatics are also present. This preferred class includes straightrun gasolines, natural gasolines, synthetic gasolines and the like. Onthe other hand, it is frequently advantageous to charge thermally orcatalytically cracked gasolines or higher boiling fractions thereof.Mixtures of straight run and cracked gasolines can also be used toadvantage. The gasoline charge stock may be a full boiling gasolinehaving an initial boiling point of from about 50 F. to about 150 F. andan end boiling point within the range of from about 325 F. to about 425F., or may be a selected fraction thereof which generally will be ahigher boiling fraction commonly referred to as a heavy naphthaforexample, a naphtha boiling in the range of C to 400 F. In some cases, itis also advantageous to charge pure hydrocarbons or mixtures ofhydrocarbons that have been extracted from hydrocarbon distillates-forexample, straight-chain paraflinswhich are to be converted to aromatics.It is preferred that these charge stocks be treated by conventionalcatalytic pretreatment methods such as hydrorefining, hydrotreating,hydrodesulfurization, etc., to remove substantially all sulfurous,nitrogenous and Water-yielding contaminants therefrom, and to saturateany olefins that may be contained therein.

In other hydrocarbon conversion embodiments, the charge stock will be ofthe conventional type customarily used for the particular kind ofhydrocarbon conversion being effected. For example, in a typicalisomerization embodiment the charge stock can be a parafiinic stock richin C to C normal parafiins, or a normal butanerich stock or ann-hexane-rich stock or a mixture of xylene isomers, etc. Inhydrocracking embodiments the charge stock will be typically a gas oil,heavy cracked cycle oil, etc. In addition, alkylaromatic and naphthenescan be conveniently isomerized by using the catalyst of the presentinvention. Likewise, pure hydrocarbons or substantially purehydrocarbons can be converted to more valuable products by using thecatalyst of the present invention in any of the hydrocarbon conversionprocesses known to the art that use a dual-functioning catalyst.

In a reforming embodiment it is generally preferred that the novelcatalytic composite is utilized in a substan tially water-freeenvironment. Essential to the achievement of this condition in thereforming zone is the control of the water level present in the chargestock and the hydrogen stream which is being charged to the zone. Bestresults are ordinarily obtained when the total amount of water enteringthe conversion zone from any source is held to a level less than 50p.p-.m. and preferably less than 20 p.p.m., expressed as weight ofequivalent water in the charge stock. In general, this can beaccomplished by careful control of the water present in the charge stockand in the hydrogen stream; the charge stock can be dried by using anysuitable drying means known to the art such as a conventional solidadsorbent having a high selectivity for water; for instance, sodium orcalcium crystalline aluminosilicates, silica gel, activated alumina,molecular sieves, anhydrous calcium sulfate, high surface area sodiumand the like adsorbents. Similarly, the water content of the chargestock may be adjusted by suitable stripping operations in afractionation column or like device. And in some cases, a combination ofadsorbent drying and distillation drying may be used advantageously toeffect almost complete removal of water from the charge stock.Preferably, the charge stock is dried to a level corresponding to lessthan 20 ppm. of H 0 equivalent. In general, it is typically a goodpractice to dry the hydrogen stream entering the hydrocarbon conversionzone down to a level of about 10 vol. p=.p.m. of water or less. This canbe conveniently accomplished by contacting the hydrogen stream with asuitable desiccant such as those mentioned above.

In the reforming embodiment, an efll'uent stream is withdrawn from thereforming zone and passed through a cooling means to a separation zone,typically maintained at about 25 to 150 F., wherein a hydrogen-rich gasis separated from a high octane liquid product, commonly called anunstabilized reformate. Preferably, at least a portion of thishydrogen-rich gas is withdrawn from the separating zone and passedthrough an adsorption zone containing an adsorbent selective for water.The resultant substantially water-free hydrogen stream is then recycledthrough suitable compressing means back to the reforming zone. Theliquid phase from the separating zone is then typically withdrawn andcommonly treated in a fractionating system in order to adjust the butaneconcentration, thereby controlling front end volatility of the resultingreformate.

The conditions utilized in the numerous hydrocarbon conversionembodiments of the present invention are those customarily used in theart for the particular reaction or combination of reactions that is tobe effected. For instance, alkylaromatic and paraflin isomerizationconditions include: a temperature of about 32 F. to about 1000 F. andpreferably about 75 to about 600 F.; a pressure of atmospheric to aboutatmospheres; a hydrogen to hydrocarbon mole ratio of about 0.5:1 toabout 20:1, and an LHSV (calculated on the basis of equivalent liquidvolume of the charge stock contacted with the catalyst per hour dividedby the volume of conversion zone containing catalyst) of about 0.2 hr.-to 10 hr. Dehydrogenation conditions include: a temperature of about 700to about 1250 F., a pressure of about 0.1 to about 10 atmospheres, aliquid hourly space velocity of about 1 to 40 hr:- and a hydrogen tohydrocarbon mole ratio of about 1:1 to 20:1. Likewise, typicallybydrocracking conditions include: a pressure of about 500 p.s.i.g. toabout 3000 p.s.i.g.; a temperature of about 400 F. to about 900 R; anLHSV of about 0.1 hr.- to about 10 hr. and hydrogen circulation rates ofabout 1000 to 10,000 s.c.f. per barrel of charge.

In the reforming embodiment of the present invention the pressureutilized is selected from the range of about p.s.i.g. to about 1000p.s.i.g., with the preferred pressure being about 50 p.s.i.g. to about350 p.s.i.g. Particularly good results are obtained at low pressure;namely, a pressure of about 75 to 200 p.s.i.g. In fact, it is a singularadvantage of the present invention that it allows stable operation atlower pressure than have heretofore been successfully utilized inso-called continuous reforming systems (i.e., reforming for periods ofabout 15 to about 200 or more barrels of charge per pound of catalystwithout regeneration). In other words, the catalyst of the presentinvention allows the operation of a continuous reforming system to beconducted at lower pressure (i.e., 50 to about 350 p.s.i.g.) for aboutthe same or better catalyst life before regeneration as has beenheretofore realized with conventional platinum catalysts at higherpressures (i.e., 400 to 600 p.s.i.g.). On the other hand, the stabilityfeature of the present invention enables reforming operations connectedat pressures of 400 to 600 p.s.i.g. to achieve substantially increasedcatalyst life be fore regeneration.

Similarly, the temperature required for reforming is generally lowerthan that required for a similar reforming operation using a highquality platinum catalyst of the prior art. This significant anddesirable feature of the present invention is a consequence of theselectivity of the catalyst of the present invention for theoctane-upgrading reactions that are preferably induced in a typicalreforming operation. Hence, the present invention required a temperaturein the range of from about 800 F. to about 1100 F. and preferably about900 F. to about 1050 F. As is well known to those skilled in thecontinuous reforming art, the initial selection of the temperaturewithin this broad range is made primarily as a function of the desiredoctane of the product reformate considering the characteristics of thecharge stock and of the catalyst. Ordinarily, the temperature then isthereafter slowly increased during the run to compensate for theinevitable deactivation that occurs to provide a constant octaneproduct. Therefore, it is a feature of the present invention that therate at which the temperature is increased in order to maintain aconstant octane product is substantially lower for the catalyst of thepresent invention than for the high quality platinum reforming catalystwhich is manufactured in exactly the same manner as the catalyst of thepresent invention except for the inclusion of the Group IV-A metalliccomponent and the Group VI-B component. Moreover, for the catalyst ofthe present invention, the 0 yield loss for a given temperature increaseis substantially lower than for a high quality platinum reformingcatalyst of the prior art. In addition, hydrogen production issubstantially higher.

The reforming embodiment of the present invention also typicallyutilizes sufficient hydrogen to provide an amount of about 1 to about 20moles of hydrogen per mole of hydrocarbon entering the reforming zone,with excellent results being obtained when about 5 to about moles ofhydrogen are used per mole of hydrocarbon. Likewise, the liquid hourlyspace velocity (LHSV) used in reforming is selected from the range ofabout 0.1 to about 10 hr. with a value in the range of about 1.0 toabout 5 hr:- being preferred. In fact, it is a feature of the presentinvention that it allows operations to be conducted at higher LHSV thannormally can be stably achieved in a continuous reforming process with ahigh quality platinum reforming catalyst of the prior art. This lastfeature is of immense economic significance because it can allow acontinuous reforming process to operate at the same throughput with lesscatalyst inventory than that heretofore used with conventional reformingcatalysts at no sacrifice in catalyst life before regeneration.

14 The following examples are given to illustrate further thepreparation of the catalytic composite of the present invention and theuse thereof in the conversion of hydrocarbons. It is understood that theexamples are intended to be illustrative and not restrictive.

EXAMPLE I This example demonstrates a particularly good method ofpreparing the preferred catalytic composite of the present invention.

An alumina carrier material comprising A inch spheres was prepared by:forming an aluminum hydroxyl chloride sol by dissolving substantiallypure aluminum pellets in a hydrochloric acid solution, addinghexamethylene-tetramine to the resulting sol, gelling the resultingsolution by dropping it into an oil bath to form spherical particles ofan aluminum hydrogel, aging and washing the resulting particles andfinally drying and calcining the aged and washed particles to formspherical particles of gammaalumina containing about 0.3 wt. percentcombined chloride. Additional details as to this method of preparing thepreferred carrier material are given in the teachings of US. Pat. No.2,620,314.

A measured amount of germanium tetrachloride was dissolved in anhydrousethanol to make a first solution. This solution was then aged and anequilibrium condition was established therein. A second solutioncontaining water, chloroplatinic acid, ammonium tungstate and hydrogenchloride was then prepared. The two solutions were then intimatelyadmixed and used to impregnate the gamma-alumina particles in amounts,respectively, calculated to result in a final composite containing 0.1wt. percent W, 0.2 wt. percent Ge, and 0.375 wt. percent Pt. In order toinsure uniform distribution of the metallic components throughout thecarrier material, this impregnation step was performed by adding thecarrier material particles to the impregnation mixture with constantagitation. In addition, the volume of the solution was about two timesthe volume of the carrier material particles. The impregnation mixturewas maintained in contact with the carrier material particles for aperiod of about /2 hour at a temperature of about 70 F. Thereafter, thetemperature of the impregnation mixture was raised to about 225 F. andthe excess solution was evaporated in a period of about 1 hour. Theresulting dried particles were then sub jected to a calcinationtreatment in an air atmosphere at a temperature of about 925 F. forabout 1 hour. The calcined spheres were then contacted with an airstream containing H 0 and HCl in a mole ratio of about 40:1 for about 4hours at 975 F. in order to adjust the halogen content of the catalystparticles.

The resulting catalyst particles were analyzed and found to contain, onan elemental basis, about 0.375 wt. percent platinum, about 0.2 wt.percent germanium, about 0% wt. percent tungsten and about 0.63 wt.percent chlori e.

Thereafter, the catalyst particles were subjected to a dry pre-reductiontreatment by contacting them for 1 hour with a substantially purehydrogen stream containing less than 20 vol. p.p.m. H O at a temperatureof about 1000 F., a pressure slightly above atmospheric and a flow rateof the hydrogen stream through the catalyst particles cor- ;fisppndingto a gas hourly space velocity of about 720 EXAMPLE ]I In order tocompare the novel catalyst composite of the present invention with anall platinum composite of the prior art in a manner calculated to bringout the interaction of the germanium and tungsten components with theplatinum components, a comparison test was made between the catalyst ofthe present invention, which was prepared according to the method givenin Example I, and a high quality commercial reforming catalystcomprising a combination of 0.75 wt. percent platinum and 0.9 wt.percent chloride with an alumina carrier material. That is, the controlcatalyst was a combination of platinum and chlorine with a gamma-aluminacarrier material, which was prepared by a method analogous to that givenin Example I except for the inclusion of the germanium and tungstencomponents.

These catalyst were then separately subjected to a high stressevaluation test designed to determine their relative activity andselectivity for the reforming of a gasoline charge stock. In all teststhe same charge stock was utilized, its characteristics are given inTable I. It is to be noted that this test is conducted under asubstantially water-free condition with the only significant source ofwater being the 5.9 wt. p.p.m. present in the charge stock.

TABLE I.ANALYSIS OF HEAVY KUWAIT NAPHTHA Paraifins, vol. percent 71Naphthenes, vol. percent 21 Water, p.p.m 5.9 Octone No., F-l clear 40.0

This test was specifically designed to determine in a very short timeperiod whether the catalyst being evaluated has superior characteristicsfor the reforming process. It consists of a series of six 10 hour testperiods each of which is run at a constant temperature. During eachperiod a C product reformate is collected and analyzed. It was performedin a laboratory scale reforming plant comprising a reactor containingthe catalyst, hydrogen separation zone, a debutanizer column, a suitableheating, pumping, and condensing means, etc.

In this plant, a hydrogen recycle stream and the charge stock arecommingled and heated to the desired conversion temperature. Theresulting mixture is then passed downflow into a reactor containing thecatalyst as a fixed bed. An etfiuent stream is then withdrawn from thebottom of the reactor, cooled to about 55 F. and passed to theseparating zone wherein a hydrogen-rich gaseous phase separates from aliquid phase. A portion of the gaseous phase is continuously passedthrough a high surface area sodium scrubber and the resultingsubstantially waterfree hydrogen stream recycled to the reactor in orderto supply hydrogen for the reaction, and the excess over that needed forplant pressure is recovered as excess separator gas. Moreover, theliquid phase from the separating zone is withdrawn therefrom and passedto the debutanizer column wherein light ends are taken overhead asdebutanizer gas and a C reformate stream recovered as bottoms.

Conditions utilized in this test are: a constant temperature of about973 F. for the first three periods followed by a constant temperature ofabout 1007 F. for the last three periods, a liquid hourly space velocityof 3.0, an outlet pressure of the reactor of 100 p.s.i.g., and a moleratio of hydrogen to hydrocarbon entering the reactor of 5.6: 1. Thistwo temperature test is designed to quickly and efficiently yield twopoints on the yield-octane curve for the particular catalysts. Theconditions utilized are selected on the basis of experience to yield themaximum amount of information on the capability of the catalyst beingtested to respond to a high severity operation.

The results of the separate tests performed on the catalyst of thepresent invention and the control catalyst are presented for each testperiod in Table II in terms of inlet temperature to the rea n degreesnet excess 16 separator gas in standard cubic feet per barrel of charge(s.c.f./bbl.), debutanizer overhead gas in s.c.f./bbl., the ratio of thedebutanizer gas make to the total gas make, and F-l clear octane number.

Catalyst of the present invention-0.375 wt. percent platinum, 0.1 wt.percent tungsten, 0.2 wt. percent germanium, and 0.65 wt. percentchlorine Control catalyst-0.75 wt. percent platinum, and 0.9

wt. percent chlorine Referring now to the results, given in Table II, ofthe separate tests performed on these catalysts, it is evident that theetfect of the combination of a germanium component with a tungstencomponent is to substantially promote the platinum component. That is,the catalyst of the present invention is sharply superior to the controlcatalyst in both activity and selectivity. As was pointed outhereinbefore, a good measure of activity for a reforming catalyst isoctane number of reformate produced at the same conditions; on thisbasis, the catalyst of the present invention was more active than thecontrol catalyst at both temperature conditions. However, activity isonly half of the story: activity must be coupled with selectivity todemonstrate superiority. Selectivity is measured directly by referenceto C yield and indirectly by reference to separator gas make, which isroughly proportional to net hydrogen make which, in turn, is a productof the preferred upgrading reactions, and by reference to debutanizergas make which is a rough measure of undesired hydrocracking and shouldbe minimized for a highly selective catalyst. Referring again to thedata presented in Table II and using the selectivity criteria, it ismanifest that the catalyst of the present invention is materially moreselective than the control catalyst.

It is intended to cover by the following claims all changes andmodifications of the above disclosure of the present invention whichwould be self-evident to a man of ordinary skill in the catalystformulation art and/or in the hydrocarbon conversion art.

I claim as my invention:

1. A process for improving a gasoline fraction which comprises reformingsaid fraction in contact with a catalytic composite comprising a porouscarrier material having combined therewith, on an elemental basis, about0.01 to about 2 wt. percent of platinum, about 0.01 to about 3 wt.percent of tungsten and about 0.1 to about 5 wt. percent of germanium.

2. A process as defined in claim 1 wherein the porous carrier materialis a refractory inorganic oxide.

3. A process as defined in claim 2 wherein the refractory inorganicoxide is alumina.

4. A process as defined in claim 1 wherein the catalytic compositecontains a halogen component.

5. A process as defined in claim 4 wherein the halogen component of thecomposite is chlorine or a compound of chlorine.

6. A process as defined as in claim 1 wherein the atomic ratio oftungsten to platinum contained in the composite is about 0.05:1 to about4:1 and wherein the 17 atomic ratio of germanium to the platinumcontained in the composite is about 0.05:1 to about 10:1.

7. A process as defined in claim 1 wherein the contacting is conductedin the presence of hydrogen.

8. A process as defined in claim 7 wherein the reforming is at atemperature of about 800 to about 1100 F., a pressure of about 0 toabout 1000 p.s.i.g., a liquid hourly space velocity of about 0.1 toabout 10 hr.- and a mole ratio of hydrogen to hydrocarbon of about 1:1to about 20: 1.

9. A process as defined in claim 8 wherein the pressure is about 50 toabout 350 p.s.i.g.

10. A process as defined in claim 7 wherein the contacting is performedin a substantially water-free environment.

References Cited UNITED STATES PATENTS 10 DELBERT E. GAN'I'Z, PrimaryExaminer S. L. BERGER, Assistant Examiner OTHER REFERENCES

